Diplomacy is a strategic board game developed by Allan B. Calhamer and originally released in 1959. It is a game about negotiations, alliances and promises you either live up to or break.
The players take the role of seven nations which are struggling for power in the Europe of the beginning 20th century with the goal to conquer and control the majority of Europe. To get there, the game is played in a series of negotiation phases and movement phases.
During the negotiation phases the players talk to each other privately or in small groups to forge plans, enter alliances, make promises or propose strategies. After the negotiations everyone writes down the orders for his units in secret.
During the movement phase all written orders of all players are executed simultaneously. It now shows who kept his promises, who works with whom and who you can really trust.
A more detailed explanation can, for example, be found on the website of the German Diplomacy Association. Additionally I would like to point out an introductory video I made that explains the basics of the game (in German).
There are loads of places where you can play Diplomacy online directly or via e-mail. The nicest way to play Diplomacy is probably face to face, though, where all players sit around a table and negotiate with each other face to face.
DipInit is an application I created to easily allocate the countries for a game of Diplomacy based on the preferences of the seven players, a tedious task to do manually. Head on over to the Apps & Code page for further information on both the Mac app of DipInit as well as the web application to use with a browser or on your smartphone.
I am and have been game mastering several games of Diplomacy, some of which you can find in the list below. Following the links you have access to all game related information and adjudications.